Method for control of paraffin deposition



METHOD FGR CONTROL or PARAFFIN nnrosrrroN Donald L. Andersen, Minneapolis, and Jean B. Thielen, St. Paul, Minn, assignors to General Mills, Inc, a

. corporation of Delaware I No Drawing. Filed Sept. 19, 1960, SEE. Nelsen/s 8 Claims. c1. zen-8.3

The present invention relates to a method for preventing the deposition in oil well production equipment, etc. o-fth'e parafiinlike solid hydrocarbon materials contained in .petrol-iferous fluids. Moreparticularly, the present invention relates to the use of chemical compounds, as parafiin deposition inhibiting agents.

The problem of parafiin deposition has been one of long standing in many phases of the oil industry. The socalled parafiin deposition occurs in flow lines, in pump? ing rods, tubing, and at other points which come in contact with the crude oil. The term parafiin as used in this context by those skilled in the art, refers to any ma-.

terial which is insoluble or undispersible in crude oil under conditions of production. Thus, the paraffin deposit may contain high molecular weight aliphatic hydrocarbons (straight and branched chains), resins, asphaltie materials,

water andasand. As will be'understood, of course, the composition of such a deposit varies from one crude oil type to another, from one well to another in the same area, and from one geographic location to another.

In the past a great variety of treatments have been used to prevent the depositionfof paraflin. One of the more common methods has been the physical treatment using scraping devices and heating devices. Chemical solvents have also been used to remove deposits. In fact, some solvent formulations were developed that will react in part with thewell fluid to produce heat in addition to the solvent action. Still other chemical formulations were used to form a solubleYplug which has both mechanical i and solvent functions. Eltorts have even been'made to plastic co at andotherwise treat pipes to prevent deposition. In some instances even combinations of all these methods have been used, but the problem still remains.

. .The various methods each have their disadvantages. The mechanical cleaning or scraping of pipes has proven the chemical solvents proposed cause handling and toxicity problems and similarly the treating and plastic coating in which R is an aliphatic hydrocarbon group having 8 to 22 carbon atoms, A is a divalent hydrocarbon radical havingl to 6 carbon atoms, X is a member selected from the group consisting of hydrogen, an alkali metal, and an amine, and m is to l, etfectively prevent the deposition of paratfins, when added to the crude oil.

, United States Patent 0 '25 aromatic hydrocarbons, naphthalene,oil, inorganic scale,

where R is coco; and

3,102,859 Patented Sept. 3, 1963 methylated, quaternized derivatives of these acids. The structures of some of the preferred compounds are:

R-N (CH CH -CO ON',,) 2

Disodium N-ta1low-/3,,8-amino dipropionate where R is a t-allow fatty radical;

N-ta1low propylene diamine salt of N coeo-fl-aminopropionic acid, where R is coco and R is tallow;

RNH-CH --CH -COONH(CH CH OH) 3 triethanolamine salt of N-coco-flaamino-propionic acid Nalkylarnino-Ndallow-e-amino propionamide where R: tallow and R is alkyl such as tallow, octyl, or methyl.

Many of the above-described compounds are commercially avialable while others can be prepared by a variety of well known chemical reactions. The acid form of the compound is formed-by simply reacting a primary alkyl amine with an unsaturated acid such as crotonic acid, etc. or by reacting a primary alkyl mine with a lower alkyl ester of an unsaturated acid in the manner described in US. Patent 2,468,012. and then hydrolyzing the ester to the corresponding acid. The salts of the detergent v to be too expensive for wide spread adoption. Many of Representative of the compounds contemplated for use in the present invention are the detergent amino acids such aminobis-crotonic acid; the alkali metal and amine salts of the detergent amino acids; the zwitterion form of the detergent amino acids; and the ethoxylated, sulfonated,

amino acids are readily formed by conventional methods,

whereas, the zwitterion form of the detergent amino acid is obtained by adding a non-oxidizing acid to the alkali metal salt as described in US. Patent 2,816,920. The

various ethoxylated, sulfonated, methylated and quaternized derivatives are likewise prepared by conventional methods.

While single isolated primary amines are used with excellent results in preparing the :above-described compounds, the mixture of amines obtained by the amination of the mixed fatty acids or selected fractions thereof present in common fats and oils are preferred because of their availability. Typical of such amines are coco amine which contains fatty groups of from 8 to 18 carbon atoms and tallow amine which contains fatty groups of from 8 to 22 carbon atoms and which are obtained by the amination of the fatty acids or fractions thereof found in coconut oil and tallow, respectively.

In the practice of the present invention the amount of fluidizing agent to be employed is not critical and will vary with the nature of the petroliferous liquid encountered. In general, however, it can be said that satisfactory results are obtained when .01 to 1% of the agent, by weight of the paraffin content, is employed. Of course, when treating parafiin deposits which already exist, larger amounts of the agent may be advantageously employed. In either event the determination of optimum amount of agent tobe employed is best determined by trial.

The present invention is further illustrated by reference to the following examples. Unless otherwise indicated all parts :and percentages used herein are by weight.

The etfifectiveness of a parafiin inhibitor is best evaluated by the laboratory test procedure set forth below.

Various paraffin inhibitors to be tested were weighed into 5.0 cc. centrifuge tubes, 30 g. of theparaflin-containing crude oil was added and the contents thoroughly mixed by vigorously shaking the tube by hand. The centrifuge tube was placed in a model W2-801 centrifuge made by International Clinical Centrifuge Company and centrifuged for 5 minutes. The centrifuge tubes were removed from the centrifuge and the supernatant liquid decanted. The parwas subjected to the same treatment in the absence of an inhibitor. The results of this testing is shown in Table I. Some of the solid materials are more conveniently sition'inhi'biting agent is disodium .N-tal low-fifiiminodipropionate.

3. The method of claim l-wherein the paraffin deposition inhibiting agent is N-coco-fi-arninopropionic acid,

added to the crude oil as solutions. If a solvent was used 5 4. The method of claim 1 wherein the paraflin depoit is listed in the third column of Table I. Following the sition inhibiting agent is N-tallovvpropylene diaruine salt solvent the ratioof solvent to inhibitor in the solution. of N-cooo-B-aniinopropionic acid.

Table l Inhibitor Inhibitor Parafiin V Example Inhibitor solvent concenconcen- Description of results tration, tration, j percent percent 1 Disodium N-tal1ow-fl,fl-amino-diprowater (6:1). 0.3 10 Precipitate was approximately the pionate. same volume as the control, but the precipitate was quite fluid and pourable. do n0ne.. 0.5 v Volume of precipitate reduced 50%.

N-coco-fi-amino-proplonic acid kerosene (1:1). 0.5 10 Do. I do do 0.5 20 Do. N-ta1low propylene diamine salt of none 0.5 10 Do.

.N-coco-flemino-propionic acid. Triethanolamine salt of N-coco-B- do 0.3 Do.

amino-propionic acid. N-tallow-fl-amino-propionic acid kerosene 0.3 10 Volume of precipitate reduced 25%. Methyl-Ntallow-fl-amino propionate none 0.5 I 10 Do. N-a1kylamino-N-talloW-fi'aminoxylene (3:2). 0.8 10 Volume of precipitate reduced 50%.

propionamide where the alkyl is 8 and 10 carbon straight chain. N-ta1low arnino-N-tallow-B-aminodo 0.8 10 Do.

propionamide.

As clearly demonstnated, the inhibitor sharply reduces the 5. The method of claim 1 wherein the paraflin deposideposition even under the unusually severe conditions of J tion inhibiting agent is the triethanol amine salt of N-coco this test. IS-amino propionic aci The foregoing examples :are intended as illustrations of preferred embodiments of thepresent invention and are not to be interpreted as limitations on the scope thereof.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as followsz 1. The method of preventing the deposition of paraffin contained in p etroli-ferou-s fluids which comprises adding to said fluids a parafiin deposition inhibiting agent of the formula:

RNH (A-C-OOX) in which R is an aliphatic hydrocarbon group having 8 to 22 carbon atoms, A is a divalent hydrocarbon radical 6. The method of claim 1 wherein the paraflin deposition inhibiting agent is N-tallow-B-aminopropionic acid.

7. The method of claim 1 wherein the paraflin deposition inhibiting agent is N alkylarninc-N-tallow-p-amino propionamide.

8. The method of claim 'l wherein the paraffin deposiis methyl-N-tailow-fi aminopropio-' tion inhibiting agent natef I g References Cited in the-file of this patent UNITED STATES PATENTS 2,468,012 Isrbell 1- Apr. 19, 1949 2,602,778 Snyder et al. July 8, 1952 2,619,467 Isbell "N*o v 25, 1952 2,802,784 Nowak et a1 Apr} 13-, 1957 2,836,559 Beck et a1 May 27, 1958 2,873,253 Stanp'hill Feb. 10, 1959 2,926,108

Anderson Feb. 23, 19 

1. THE METHOD OF PREVENTING THE DEPOSITION OF PARAFFIN CONTAINED IN PETROLIFEROUS FLUIDS WHICH COMPRISES ADDING TO SAID FLUIDS A PARAFFIN DEPOSITION INHIBITING AGENT OF THE FORMULA: 